Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
  • C08G18/3819—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen
  • C08G18/3821—Carboxylic acids; Esters thereof with monohydroxyl compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step

Definitions

• the present invention relates to 4-chloro-3,5-diaminophenyl acetates, preparations thereof and curing agents for polyurethane elastomer using the same compound.
• aromatic diamines are used as curing agents for polyurethane elastomer.
• Various aromatic diamines have been proposed.
• various characteristics have been required for curing agents used for polyurethane elastomer and satisfactory aromatic diamines could not be obtained.
• the characteristics required for curing agent include
• 3,3'-dichloro-4,4'-diaminodiphenyl methane is a curing agent for polyurethane elastomer having excellent mechanical characteristics, however, it has high melting point (100° to 106° C.) whereby the processability is disadvantageously inferior.
• the inventors have studied to obtain a curing agent which has the satisfactory characteristics required for the curing agent for polyurethane elastomer and have synthesized many compounds.
• novel compounds of the present invention are 4-chloro-3,5-diaminophenyl acetates having the formula ##STR2## wherein R represents an alkyl group.
• novel compounds of 4-chloro-3,5-diaminophenyl acetates include the following compounds:
• novel compounds of 4-chloro-3,5-diamonophenyl acetates can be obtained by simultaneously nitrating and hydrolyzing 4-chlorobenzylcyanide and esterifying the resulting 4-chloro-3,5-dinitrophenyl acetate and reducing the resulting 4-chloro-3,5-dinitrophenyl acetate.
• the reactions are shown as follows. ##STR3##
• 4-chloro-benzylcyanide is mixed with 5 to 20 molar times, preferably 7 to 15 molar times of 95 to 98% sulfuric acid at lower than 30° C. and 2.5 to 4 molar times of 60 to 99% nitric acid is added at 20° to 40° C. and a reaction is performed at 20° to 40° C. for 0.5 to 2 hours and at 50° to 70° C. for 5 to 9 hours. After the reaction, the resulting reaction mixture is poured into water and the precipitated crystals are filtered to obtain 4-chloro-3,5-dinitrophenyl acetic acid in high yield.
• the esterification of 4-chloro-3,5-dinitrophenyl acetic acid is performed by reacting with an aliphatic alcohol in the presence of an acid catalyst or in the presence of an acid catalyst and an azeotropic solvent.
• Suitable acid catalysts are inorganic or organic acids used in esterification of an acid and an alcohol such as hydrochloric acid, sulfuric acid and p-toluenesulfonic acid, etc.
• Suitable azeotropic solvents are solvents to form azeotropic mixtures with the aliphatic alcohol used in the reaction and water formed by the reaction, such as carbon tetrachloride, benzene, toluene, xylene and cyclohexane.
• the reaction temperature is usually in a range of 50° to 150° C. preferably a refluxing temperature of the reaction mixture and the reaction time is in a range of 2 to 15 hours.
• 4-chloro-3,5-dinitrophenyl acetic acid is reacted with a chlorinating agent such as phosphorus pentachloride and thionyl chloride and the resulting 4-chloro-3,5-dinitrophenyl acetic chloride is reacted with an aliphatic alcohol in the presence of dehydrogen chloride agent in the absence of a solvent or in an inert solvent.
• a chlorinating agent such as phosphorus pentachloride and thionyl chloride
• 4-chloro-3,5-dinitrophenyl acetic chloride is reacted with an aliphatic alcohol in the presence of dehydrogen chloride agent in the absence of a solvent or in an inert solvent.
• Suitable inert solvents include carbon tetrachloride, benzene, toluene and xylene.
• Suitable dehydrogen chloride agents include organic tertiary amines and inorganic bases such as triethylamine, pyridine, sodium hydroxide, potassium hydroxide and sodium carbonate.
• the reaction temperature is in a range of 0° to 150° C. and the reaction time is in a range of 1 to 6 hours.
• Suitable aliphatic alcohols used in the esterification of 4-chloro-3,5-dinitrophenyl acetic acid include methanol, ethanol, n- or i-propanol, n-, i- or sec-butanol, n- or i-amyl alcohol, n-hexyl alcohol and n-octyl alcohol.
• a solution of 4-chloro-3,5-dinitrophenyl acetate in a solvent such as benzene, toluene and xylene is added to a mixture of iron powder, an acid, water and a solvent such as benzene, toluene and xylene and the reaction is performed by refluxing for 1 to 10 hours.
• the reaction mixture is treated by a conventional purification to obtain 4-chloro-3,5-diaminophenyl acetates in high yield.
• the curing agent is heat-melted and admixed with a heated reaction mixture of a polyisocyanate and a polyol or a prepolymer having terminal isocyanato group or a polyisocyanate is admixed with a mixture of a polyol and the curing agent.
• the mixture is thoroughly mixed and poured into a mold to cure it.
• Suitable polyisocyanates include hexamethylenediisocyanate (HMDI), cyclohexanediisocyanate, 2,4-tolylenediisocyanate (2,4-TDI), 2,6-tolylenediisocyanate (2,6-TDI) and mixture of 2,4-tolylenediisocyanate and 2,6-tolylenediisocyanate, dimer and trimer of 2,4-tolylenediisocyanate, xylylenediisocyanate (XDI), meta-xylylenediisocyanate (MXDI), m-phenylenediisocyanate, 4,4'-biphenyldiisocyanate, diphenylehter-4,4'-diisocyanate, 3,3'-ditoluene-4,4'-diisocyanate (TODI), dianisidinediisocyanate (DADI), 4,4'-diphenyl
• Suitable polyols include polyols having a molecular weight of 500 to 8,000 and two or more hydroxyl groups such as aliphatic polyester glycols obtained by condensing an aliphatic glycol and a dicarboxylic acid and chain-extending it such as polyethyleneadipate, polybutyleneadipate and polypropyleneadipate; polyalkyleneether glycols obtained by a ring-opening polymerization of ethyleneoxide, propyleneoxide or tetrahydrofuran such as polypropyleneetherglycol and tetramethyleneether glycol; polyesterglycols obtained by a ring-opening polymerization of ⁇ -caprolactone; terminal hydroxylated polybutadiene; alkyleneoxide copolymers; copolyesters of glycol and a dicarboxylic acid; polyesterpolyols as copolyesters of long chain diols of mixture of aromatic glycols or a mixture of polyol e
• glycerin and trimethylolpropane and an aliphatic glycol and a dicarboxylic acid and polyetherpolyols obtained by a ring-opening polymerization of ethyleneoxide, propyleneoxide or tetrahydrofuran with an initiator of a polyol such as glycerin and trimethylolpropane.
• Suitable urethaneprepolymers having terminal isocyanates are obtained by reacting said polyol with excess of said polyisocyante such as prepolymers having terminal isocyanate group derived from a polyether or a polyesterglycol; such as prepolymers obtained by reacting polytetramethyleneglycol with excess of tolylenediisocyanate; prepolymers obtained by reacting polyethyleneadipate with excess of tolylenediisocyanate, prepolymers obtained by reacting polycaprolactonediol with excess of tolylenediisocyanate.
• a ratio of the curing agent of 4-chloro-3,5-diaminophenyl acetate of the present invention is depending upon a polyol, a polyisocyanate or a prepolymer having terminal isocyanate group and it is usually in a range of about 0.8 to 1.2 preferably 0.80 to 1.0 equivalent of amino group of the curing agent or a total of amino group of the curing agent and hydroxyl group of the polyol per 1 equivalent of the isocyanate group.
• a ratio of hydroxyl group of the polyol to the amino group of the curing agent can be varied in broad range and preferably in a range of 0.5 to 5 equivalent of hydroxyl group per 1 equivalent of the amino group.
• the curing agents of the present invention are solids having a low melting point whereby the processability is highly improved in comparison with the use of the conventional curing agent and polyurethane elastomers having excellent mechanical characteristics can be advantageously obtained.
• the reaction was performed at 30° C. for 1 hour and then, at 60° C. for 7 hours. After the reaction, the resulting reaction mixture was poured into 2 liters of ice water and a precipitated crystal was separated by a filtration and washed with water and dried to obtain 124.0 g of pale yellow powdery crystals having a melting point of 167.5° to 172.0° C. of 4-chloro-3,5-dinitrophenyl acetic acid (95.2% of yield based on 4-chlorobenzylcyanide).
• the compound was also identified by NMR.
• Example 1 In accordance with the process of Example 1 except using ethanol and ethyl 4-chloro-3,5-dinitrophenyl acetate instead of methanol and methyl 4-chloro-3,5-dinitrophenyl acetate, the reaction was carried out to obtain ethyl 4-chloro-3,5-diaminophenyl acetate. The results are shown in Table 1.
• Example 1 In accordance with the process of Example 1 except using various aliphatic alcohol, 150 ml of toluene instead of methanol; and using various 4-chloro-3,5-dinitrophenyl acetate instead of methyl 4-chloro-3,5-dinitrophenyl acetate, the reactions were carried out to obtain various 4-chloro-3,5-diaminophenyl acetates. The results are shown in Table 1.
• the compound No. 1 of methyl 4-chloro-3,5-diaminophenyl acetate was used as a curing agent. 10.2 Gram of the compound No. 1 was melted and mixed with 100 g of a prepolymer obtained from polytetramethyleneglycol and tolylenediisocyanate (Adiplene L-100 manufactured by Du Pont) (4.19 wt.% of isocyanato group) at 90° C. with stirring for about 60 seconds. The mixture was poured into a mold having a size of 100 mm ⁇ 250 mm ⁇ 2 mm heated at 100° C. and it was cured at 100° C. for 1 hour and it was demolded and then, heated at 100° C. for 15 hours to perform an after-curing. The resulting polyurethane elastomer was aged at 25° C. in a relative humidity of 50% for 7 days and characteristics of the polyurethane elastomer were measured by Japanese Industrial Standard K 6301. The results are shown in Table 2.
• polyurethane elastomers were prepared and characteristics of polyurethane elastomers were measured. The results are shown in Table 2.
• polyurethane elastomers were prepared and characteristics of polyurethane elastomers were measured. The results are shown in Table 2.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyurethanes Or Polyureas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (3)

• 1978
  • 1978-03-23 JP JP3351878A patent/JPS54125633A/ja active Granted
• 1979
  • 1979-03-08 US US06/018,613 patent/US4246425A/en not_active Expired - Lifetime
  • 1979-03-21 DE DE19792911126 patent/DE2911126A1/de active Granted

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